This introduces a new Dart CLI application in the tool/ directory designed to automate the creation and validation of Agent Skills

.gitignore

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+# https://dart.dev/guides/libraries/private-files
+# Created by `dart pub`
+.dart_tool/
+
+# IntelliJ
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# Mac
+.DS_Store
+
+# Coverage
+coverage/
+
+# Validation output from the validate-skill command
+validation/

tool/README.md

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+# Skills CLI
+
+The Skills CLI simplifies the process of creating "Agent Skills" from external documentation. It allows you to crawl documentation websites to discover relevant pages and then uses Generative AI (Gemini) to convert those pages into structured `SKILL.md` files that agents can use.
+
+## Context
+
+*   [Agent Skills Best Practices](https://platform.claude.com/docs/en/agents-and-tools/agent-skills/best-practices)
+
+## Prerequisite
+
+This tool requires the `GEMINI_API_KEY` environment variable to be set.
+
+## Commands
+
+### `generate-skill`
+
+Generates `SKILL.md` files from a JSON configuration file. Use the `--skill` option to generate a specific skill.
+
+**Usage:**
+```bash
+dart run skills generate-skill [options] [config_file]
+```
+
+**Arguments:**
+*   `[config_file]`: Path to the JSON configuration file. Defaults to `resources/flutter_skills.yaml`.
+
+**Options:**
+*   `--skill`: Filter to generate only the specified skill by name.
+*   `--directory` (`-d`): The directory to output the generated skill folder. Defaults to `../skills/`.
+
+### `validate-skill`
+
+Validates skills by re-generating and comparing with existing skills.
+
+**Usage:**
+```bash
+dart run skills validate-skill [options] [config_file]
+```
+
+**Arguments:**
+*   `[config_file]`: Path to the JSON configuration file. Defaults to `resources/flutter_skills.json`.
+
+**Options:**
+*   `--skill`: Validate only the specified skill by name.
+*   `--directory` (`-d`): The directory containing the generated skills. Defaults to the output directory or `../skills/`.
+*   `--thinking-budget`: The token budget for the model to "think" before generating content. Defaults to 2048.
+
+**Example:**
+Generate all skills defined in resources/flutter_skills.yaml to the skills/ directory:
+
+```bash
+dart run skills generate-skill
+```
+
+Generate only the 'flutter-layout' skill to a custom directory:
+
+```
+dart run skills generate-skill --skill flutter-layout --directory ../skills
+```
+
+### `validate-skill`
+
+Validates generated skills by re-generating them using the same source and comparing the output. This is useful for testing prompts or verifying consistency.
+
+**Usage:**
+```bash
+dart run skills validate-skill [options]
+```
+
+**Options:**
+*   `--directory` (`-d`): The directory containing the generated skills to validate. Defaults to `skills/`.
+
+**Example:**
+Validate skills in the default 'skills' directory:
+
+```bash
+dart run skills validate-skill
+```
+
+Validate skills in a custom directory:
+```
+dart run skills validate-skill --directory ../validation_results
+```
+
+## Configuration
+
+The default configuration file is located at `tool/resources/flutter_skills.yaml`. It contains a list of skill definitions:
+
+```yaml
+- name: flutter-layout
+  description: "..."
+  resources:
+    - https://docs.flutter.dev/ui/widgets/layout
+    - https://docs.flutter.dev/ui/layout
+```

tool/analysis_options.yaml

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+# This file configures the static analysis results for your project (errors,
+# warnings, and lints).
+#
+# This enables the 'recommended' set of lints from `package:lints`.
+# This set helps identify many issues that may lead to problems when running
+# or consuming Dart code, and enforces writing Dart using a single, idiomatic
+# style and format.
+#
+# If you want a smaller set of lints you can change this to specify
+# 'package:lints/core.yaml'. These are just the most critical lints
+# (the recommended set includes the core lints).
+# The core lints are also what is used by pub.dev for scoring packages.
+
+include: package:lints/recommended.yaml
+
+# Uncomment the following section to specify additional rules.
+
+# analyzer:
+#   exclude:
+#     - path/to/excluded/files/**
+
+# For more information about the core and recommended set of lints, see
+# https://dart.dev/go/core-lints
+
+linter:
+  # The lint rules applied to this project can be customized in the
+  # section below to disable rules from the `package:flutter_lints/flutter.yaml`
+  # included above or to enable additional rules. A list of all available lints
+  # and their documentation is published at https://dart.dev/lints.
+  #
+  # Instead of disabling a lint rule for the entire project in the
+  # section below, it can also be suppressed for a single line of code
+  # or a specific dart file by using the `// ignore: name_of_lint` and
+  # `// ignore_for_file: name_of_lint` syntax on the line or in the file
+  # producing the lint.
+  rules:
+    # Error Prevention
+    avoid_catches_without_on_clauses: true
+    avoid_catching_errors: true
+    avoid_returning_this: true
+    avoid_void_async: true
+    await_only_futures: true
+    cancel_subscriptions: true
+    close_sinks: true
+    discarded_futures: true
+    literal_only_boolean_expressions: true
+    no_adjacent_strings_in_list: true
+    no_logic_in_create_state: true
+    only_throw_errors: true
+    prefer_is_empty: true
+    prefer_is_not_empty: true
+    test_types_in_equals: true
+    throw_in_finally: true
+    unawaited_futures: true
+    unnecessary_null_aware_assignments: true
+    unnecessary_null_in_if_null_operators: true
+    unnecessary_nullable_for_final_variable_declarations: true
+    use_build_context_synchronously: true
+    use_rethrow_when_possible: true
+
+    # Style & Formatting
+    always_declare_return_types: true
+    always_put_required_named_parameters_first: true
+    avoid_escaping_inner_quotes: true
+    avoid_function_literals_in_foreach_calls: true
+    avoid_init_to_null: true
+    avoid_multiple_declarations_per_line: true
+    avoid_positional_boolean_parameters: true
+    avoid_private_typedef_functions: true
+    avoid_redundant_argument_values: true
+    avoid_renaming_method_parameters: true
+    avoid_shadowing_type_parameters: true
+    avoid_types_on_closure_parameters: true
+    avoid_unused_constructor_parameters: true
+    camel_case_extensions: true
+    cascade_invocations: true
+    curly_braces_in_flow_control_structures: true
+    directives_ordering: true
+    eol_at_end_of_file: true
+    file_names: true
+    library_names: true
+    no_leading_underscores_for_library_prefixes: true
+    no_leading_underscores_for_local_identifiers: true
+    omit_local_variable_types: true
+    prefer_const_constructors: true
+    prefer_const_constructors_in_immutables: true
+    prefer_const_declarations: true
+    prefer_const_literals_to_create_immutables: true
+    prefer_final_fields: true
+    prefer_final_in_for_each: true
+    prefer_final_locals: true
+    prefer_if_elements_to_conditional_expressions: true
+    prefer_interpolation_to_compose_strings: true
+    prefer_mixin: true
+    prefer_relative_imports: true
+    prefer_single_quotes: true
+    require_trailing_commas: true
+    sized_box_for_whitespace: true
+    sort_child_properties_last: true
+    sort_constructors_first: true
+    sort_unnamed_constructors_first: true
+    type_init_formals: true
+    unnecessary_await_in_return: true
+    unnecessary_breaks: true
+    unnecessary_const: true
+    unnecessary_constructor_name: true
+    unnecessary_lambdas: true
+    unnecessary_late: true
+    unnecessary_new: true
+    unnecessary_parenthesis: true
+    unnecessary_raw_strings: true
+    unnecessary_string_escapes: true
+    unnecessary_string_interpolations: true
+    unnecessary_this: true
+    use_function_type_syntax_for_parameters: true
+    use_string_buffers: true
+    use_to_and_as_if_applicable: true
+
+    # Best Practices
+    annotate_redeclares: true
+    avoid_annotating_with_dynamic: true
+    avoid_bool_literals_in_conditional_expressions: true
+    avoid_classes_with_only_static_members: true
+    avoid_print: true
+    avoid_setters_without_getters: true
+    depend_on_referenced_packages: true
+    deprecated_consistency: true
+    library_private_types_in_public_api: true
+    prefer_asserts_in_initializer_lists: true
+    prefer_constructors_over_static_methods: true
+
+    # Documentation
+    dangling_library_doc_comments: true
+    library_annotations: true
+    public_member_api_docs: true
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

tool/bin/skills.dart

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+// Copyright (c) 2026, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:io';
+
+import 'package:args/command_runner.dart';
+import 'package:http/http.dart' as http;
+import 'package:logging/logging.dart';
+import 'package:skills/src/commands/generate_skill_command.dart';
+import 'package:skills/src/commands/validate_skill_command.dart';
+
+const String version = '0.1.0';
+
+void main(List<String> arguments) async {
+  final httpClient = http.Client();
+
+  final runner = CommandRunner('skills', 'A sample command-line application.')
+    ..addCommand(GenerateSkillCommand(httpClient: httpClient))
+    ..addCommand(ValidateSkillCommand(httpClient: httpClient));
+
+  runner.argParser.addFlag(
+    'version',
+    negatable: false,
+    help: 'Print the tool version.',
+  );
+  runner.argParser.addFlag(
+    'verbose',
+    abbr: 'v',
+    negatable: false,
+    help: 'Show additional command output.',
+  );
+
+  try {
+    final results = runner.parse(arguments);
+    if (results.flag('version')) {
+      stdout.writeln('skills version: $version');
+      return;
+    }
+
+    _configureLogging(results.flag('verbose'));
+
+    if (results.flag('verbose')) {
+      Logger.root.fine('All arguments: ${results.arguments}');
+    }
+
+    await runner.run(arguments);
+  } on UsageException catch (e) {
+    stderr.writeln(e);
+    exit(64);
+  } on Exception catch (e) {
+    stderr.writeln('An error occurred: $e');
+    exit(1);
+  } finally {
+    httpClient.close();
+  }
+}
+
+void _configureLogging(bool verbose) {
+  Logger.root.level = verbose ? Level.ALL : Level.INFO;
+  Logger.root.onRecord.listen((record) {
+    if (record.level >= Level.SEVERE) {
+      stderr.writeln(record.message);
+    } else {
+      stdout.writeln(record.message);
+    }
+  });
+}